Hollow steel propeller blade construction



Jan. 3, 1950 w. c. HEATH 2,493,139

HOLLQW STEEL PROPELLER BLADE CONSTRUCTION Filed Feb. 23, 1944 3 Sheets-Sheet 1 William c. Heath INVENTOR.

ATTORNEY.

50 w. c. HEATH 2,493,139

HOLLOW STEEL PROPELLER BLADE CONSTRUCTION Filed Feb. 25, 1944 I 3 Sheets-Sheet 2 FIG. 8. 9 9 FIG. 9.

2 H610. I0 Frail.

William CJ'IEHHZ INVENTOR A TTURHZYI Jan. 3, 1950 w. c. HEATH 2,493,139

HOLLOW STEEL PROPELLER BLADE CONSTRUCTION Filed Feb. 23, 1944 3 Sheets-Sheet 3 William clHeazh "a" INV T BY 6m ETTYVQRPEEYT Patented Jan. 3, 1950 HOLLOW STEEL PROPELLER BLADE CONSTRUCTION William C. Heath, Shorewood, Wis., assignor to A. 0. Smith Corporation, Milwaukee, Wis., a corporation oi New York Application February 23, 1944, Serial No. 523,504

7 Claims.

This invention relates to hollow steel propeller blade construction and constitutes a continuation of an improvement upon the invention set forth in the copending application filed by the present inventor, Serial No. 480,682, on March 26, 1943, for Electrically'welded hollow steel propeller blade and method of making the same.

The present invention utilizes electric flash welding as set forth in said copending application for joining the parts of the blade, and it adds certain welded seams, thereby providing for a greater division of parts with more accurate forming operations and less waste. The invention is applicable to the construction of larger blades in which the problems of vibration and fluttering are more severe.

The principal objects of the invention are to further reducethe loss in material and to reduce the cost of manufacture of the blades. Another object is to provide a flash welded construction which is more stable against vibration and destruction.

In carrying out the invention, the shank is formed from semi-tubular members electrically flash welded along longitudinal lines. In the case of large blades, such as those employed for stratosphere flying, the body of the blade is made in a plurality of sections, each section being constructed of forged leading and trailing edge members, and foil plates electrically flash welded to the flanges of specially fabricated I beams, the sections being joined longitudinally and to adjacent sections of the blade by electric flash welds.

By eliminating the employment of tubular blanks for the several sections, and employing pieces forged or rolled from bar or plate stock and flash welding them together, it is possible to greatly' reduce the weight of metal in the original blanks, required to produce a finished blade of a given weight.

The invention is illustrated in the accompanying drawings in which:

Figure 1 is an isometric view of the parts prior to assembly and welding;

Fig. 2 is a plan view of the finished propeller blade;

' Fig. 3 is a central longitudinal section;

Fig. 4 is a. transverse section through the shank ofthe blade taken on line 4-4 of Fig. 2;

Fig. 5 is a transverse section through the inner body of the blade taken on line 5-5 of Fig. 2;

Fig. 6 is a. transverse section through the middle body section 01' the blade taken on line -6 of Fig. 2;

2 Fig. 7 is a transverse section through the outer body section of the blade taken on line 1-1 of Fig.2; Fig. 8 is a perspective view of a blank from which one-half of the shank is forged or rolled;

Fig. 9 is a similar view of the blank of Fig. 8

after the first longitudinal rolling operation;

Fig. 10 is a similar view of the blank of Fig. 8 after the second longitudinal rolling operation;

Fig. 11 is a similar view of the blank of Fig. 10 after a cross rolling operation in one direction;

Fig. 12 is a similar view of the blank after the second cross rolling operation;

Fig. 13 is a similar view of the blank of Fig. 12 after trimming and forming into semi-tubular shape preparatory to welding to a complementary blank for making the shank;

Fig. 14 is a transverse section showing the two parts of the shank clamped in the welding machine preparatory to welding;

Fig. 15 is a similar section showing the completed weld prior to trimming of the flash;

Fig. 16 is an isometric view of the blanks from which any one of the body sections is made;

Fig. 17 is a similar view of the forged parts for making up one of the I beams;

Fig. 18 is a perspective view of a completed I beam;

Fig. 19 is an isometric view showing the forged parts for a. body section prior to welding;

Fig. 20 is a perspective view of a blank from which a pair of tips are forged;

Fig. 21 is a similar view 01' the blank after forging;

Fig. 22 is a side edge view of the blank of Fig. 21;

Fig. 23 is a perspective view of a completed tip;

Fig. 24 is a longitudinal central sectional view of the several sections of the blade isometrically arranged as though for welding end to end; and

Fig. 25 is a detail section showing a modified construction in which the vertical webs of the I beams are not continuous longitudinally of the blade.

In manufacturing the propeller blade, each section and part are made to predetermined size and shape with the pitch and twist incorporated therein prior to assembly and welding.

The parts are made from high strength low alloy steel as set forth in the applicationabove' referred to.

The blade I is constructed of a shank 2, a pin:- rality of body sections 3, 4 and 5 and a tip 6. The sections are welded end to end to provide the completed blade.

The shank is constructed of two longitudinally extending semi-tubular halves I and 8 electric flash welded along their longitudinal meeting lines. Each half of the shank'is constructed of a rectangular block 9 of steel shown in Fig. 8 and which is first contour rolled longitudinally in successive steps as illustrated in Figs. 9 and 10. This rolling operation thins and extends one end of the blank to lengthen the same and provide a thick end edge portion ID for welding. The blank is then subjected to a cross rolling operation in one direction to provide the thick edge portion ll along one side, as shown in Fig. 11. The next cross rolling operation, illustrated in Fig. 12, is inthe opposite direction to provide the thick edge portion l2 along the other side of the blank. It is then trimmed and formed into semi-tubular shape as shown in Fig. 13. The thick edge portions I extend along the thin portion of the blank and up to thethick semi-cylindrical end at each side of the blank.

, portions [0, II and I2 of the blanks 1 and 2 0f The blank of Fig. 13 comprises a heavy semicylindrical base end l3 merging into a thin semitubular body section M of progressively greater depth ending in the thick portion ID. 'The side edges I I and I2 of the section [4 are thicker than the central part and are bent substantially straight and parallel to each other to provide edge portions which are adapted to oppose corresponding portions of a complementary blank for flash welding thereto.

The edge portions l0, II and l2are constructed with the thickening toward the inside of the blank as described in the earlier application referred to as to other blanks. .The edges may also be coated with a suitable material l5 for preventing sticking of flash, as set forth in the earlier application. In the electric flash welding operations both seams are welded simultaneously as shown in Figs. 14 and 15, and the edge portions II and I2 are partially flashed away resulting in the final seams being located in the thickest part of the portion providing strengthening beads l6 inside the shank and extending longitudinally thereofat the inside of the welds l'l.

After welding, the flash i8 is trimmed from the welded seams, and the blank is flattened at the outer end to correspond with the air foil of section 3 and then polished and balanced.

The construction of the several body sections 3, 4 and 5 is illustrated in Figs. 16 to 19, inclusive. It is generally the same as the construction of the body section disclosed in the copending application above referred to, except that where a large propeller is to be made, two I beam reinforcing members l9 are welded into the sections at the longitudinal seams.

The I beams, having variable depth from end to end and having their flanges twisted to correspond with a portion of the air foil contour of the blade, are fabricated from separate flange and web blanks as illustrated in Figs. 17 and 18. Here the upper flange blank 20 has a central depending rib 2| for butt welding to the upper edge of the central vertical web22 of the beam. Similarly, the lower flange 23 has a central rib 24 in its upper surface for butt welding to the lower edge of web 22. The web 22 is of varying width and has suitable openings 25 for lightening the same in weight. Fig. 18 illustrates the completed I beam after electric flash welding of the ribs 21 and 24 to the web 22 and trimming of the flash.

The flanges 20 and 23 may be given their air foil contour and twist during forging of the shank 2. The thickness of the flanges is preferably tapered and greater than that of the remaining air foil sections of the blade.

In constructing a body section 3, a leading edge forging 26, trailing edge forging 21, camber foil plate 28 and thrust foil plate 23 are first forged in the manner generally described in the copending application referred to. The leading and trailing edge forgings are constructed from bar stock, such as the blanks 30 and 3!, respectively, of Fig. 16. The foil plates are roll forged from plate stock, such as the blanks 32 and 33, respectively, of Fig. 16. The several parts have edge portions 34 formed with straight parallel ele- 'portions 34 extends toward the inside and tends to provide a strengthened weld seam 35 on either side of the I beam.

In making the welds 35, the I beams are preferably first welded to the leading and trailing edge forgings 26 and 21, respectively, and then to the foil plates 28 and 23. However, it is possible to weld the I beams first to the foil plates and then to the respective edge forgings. In these welding operations, two seams are flash welded simultaneously similar to the welding, of the body sections described in applicant's copending application. Upon completion of the several welding operations, the flash is trimmed from the weld. leaving a structure having a section such as that illustrated in Figs. 5, 6 and '7 for the respective body sections 3, 4 and 5 of the blade.

The I beams [9 are preferably disposed in all of the longitudinal seams of the body sections 3, 4 and 5, although it is understood that they may be left out of one or more .of the scams or sections. In the thin outer section 5, the I beams may be constructed merely of the upper and lower flanges with the central ribs welded directly together without the intermediate web 22. It is also possible to employ an I beam in the outer end of the shank 2.

The tip 6 is constructed of a round bar 33 which is upset and then pancaked in the center, as illustrated in Figs. 21 and 22. The blank is then severed transversely in the center to provide two separate tips 31, and after trimming and shaping, a slot 38 is forged or cut in the severed edge of the blank to register with the hollow end of the body section 5 when the parts are assembled. The tip has a central knob 33 at its outer curved end for use in handling and machining the blade during production. The knob I3 is removed from the blade in one of the last operations.

Each section may be statically balanced before assembly, and the several parts are repeatedly tested, as by magnaflux, during fabrication in order to detect any defects that might ultimately destroy the performance of a blade.

accuse The several sections of the blade are electric flash welded end to end in the same manner as described in the copending application. The tip 6 is first welded to the outer end of body section I. The section 5 is then welded to section I and the latter to section 3, which in turn is finally welded to the shank 2. For this purpose, each section, including the tip, has its end edge portion formed to provide an internal strengthening rib 40 at the location of each end weld I. The flash is removed from the inside and outside after each welding operation.

In welding the body sections end to end, the webs 22 are not welded together. Instead, they are cut away upon asuitable curvature to prevent engagement bleeding the welding current from the outer foil surfaces which are being welded together. The webs 22, therefore, are ordinarily separated at their respective ends. This separation is provided more effectively in the embodiment illustrated in Fig. 25 where the web comprises a plurality of separate strips spaced longitudinally along the flanges and which serve as ties between the camber and thrust faces of the blade.

The blade is then roughly balanced and its shank machined, and finally theblade is balanced and tested.

The invention provides a blade that can be constructed under carefully supervised gnass production methods and designed of large 'size for high altitude flying. The blade is well reinforced by the I beams extending longitudinally at the weld lines and by the beads and ribs strengthening the welds. By constructing the shank of two half forgings, a considerable amount of metal is saved.

as compared with prior practice of starting with a thick tubular blank. Likewise, the construction of the body sections of separately forged pieces reduces the machining operations and saves metal. With the shank alone, it is possible to start with blanks weighing a total that is over less than the weight of former blanks. The invention represents a substantial saving of expensive alloy metal for each blade.

Various embodiments of the invention may be employed within the scope of the accompanying claims:

The invention is claimed as follows:

1. A hollow metal propeller blade comprising a tubular shank section made up of a plurality of longitudinally extending separately forged complementary parts electrically flash butt welded together along longitudinal seams, a blade section made up of a plurality of separately forged parts electrically flash butt welded together with the body section of the blade constituted of leading and trailing edge members welded along longitudinal seams to the flanges of I beams and foils welded to said flanges intermediate the I beams to provide a continuous a'ir foil section with the flanges of the I beams constituting parts of the air foil surfaces between the edge members and the foil sections, and an electric flash butt weld joining the inner end of said blade section to the outer end of said shank section.

2. A hollow metal propeller blade comprising a tubular shank section constituted of separately forged leading and trailing edge members electrically flash butt welded together along longitudinal lines intermediate the leading and trailing edges of the blade and providing a heavy substantially cylindrical shank end merging into a lighter blade shaped outer end, a blade section made up of a plurality of separately forged parts'elcctrically flash butt welded together with the body section of the blade constituted of leading and trailing edge members welded along longitudinal seams to the flanges-of I beams and foils welded to said flanges intermediate the I beams to provide a continuous air foil section with the flanges of the I beams constituting parts of the air foil surfaces between the edge members and the foil sections, and an electric flash butt weld joining the inner end of said blade section .to the outer end of said shank section.

3. A hollow metal propeller blade comprising a tubular shank section providing a heavysubstantially cylindrical shank end merging into a, lighter blade shaped outer end, and a separately fabricated body section joined by a butt weld to the blade shaped outer end of said shank section and made up of separately forged leading and trailing edge members of substantially V- shaped section, separately forged camber and thrust plates, and a pair of I beam members disposed longitudinally of the body section with their upper and lower flanges butt welded to the upper and lower edges of said edge members,

tive I beams, and with the thrust plate butt welded at its edges to the other flange of the respective I beams.

4. In the manufacture of a hollow metal propeller blade from separately forged tubular sections but welded together along longitudinal and transverse lines, the construction of a separate shank section having a thick cylindrical shank end with a thinner and partially flattened blade end comprising an intermediate panel bordered by an end edge and side edges thicker than said panel by the steps of separately forging a pair of semi-tubular complementary members from flat plate stock in successive forging steps which first thin the blade portion of the blank, then form the thicker end edge of the blade portion and then form the thicker side edges of the blade portion with the intermediate panel of the blade portion of tapered thickness bordered by said thicker edges and by the thick shank portion, and electrically flash butt welding the side edges of said members together along longitudinal lines.

5. In the manufacture of a hollow metal propeller blade from separately forged tubular sections but welded together along longitudinal and transverse lines, the construction of a separate shank section having a thick cylindrical shank end with a thinner and partially flattened blade end comprising an intermediate panel bordered by an end edge and side edges thicker than said panel by the steps of separately forging leading and trailing edge members from flat plate in successive forging steps which first thin the blade portion of the blank and then form the thicker end edge of the blade portion and then form the thicker side edges of the blade portion with the intermediate panel of the blade portion bordered by said thicker edges and by the thick shank portion whereby the longitudinal edges of the blanks are matched for welding, and electrically flash butt welding said members together along longitudinal lines intermediate the leading and trailing edges of the blade.

6. In the manufacture of a hollow metal propeller blade from separately fabricated sections butt. welded together end toend, the steps of separately forging a pair of semi-tubular com- 7 Y plementarymembers and electrically flash butt welding said members together along longitudinal lines to provide a shank section having a thick cylindrical shank end with a thinner and partially flattened blade end, forging a leading edge member of generally V-shaped section, similarly forging a trailing edge member, forging camber and thrust plates, providing I beams adapted to be disposed between the respective edge members and said plates with the flanges of the I beams shaped to correspond generally to the air foil surfaces of the propeller,-electrically flash butt welding said edge members to corresponding flanges of said I beams, electrically flash butt welding said plates to said I beam flanges to complete the body section, and electric flash butt welding said body section to said shank, end to end. 7 4 7. In the manufacture of a hollow metal propeller blade, the construction of a body section by separately forging leading and trailing edge members, separately forging camber and thrust plates, fabricating a pair of I beams adapted to be disposed between said members and plates with the flanges of the I beams incorporated in and constituting an integral part of the air foil surfaces of the blade, butt welding said leading edge member to the flanges of one I beam, similarly butt welding said trailing edge member to the flanges of the other I beam, and butt welding the opposite flanges of said I beams to the respective edges of said plates.

WILLIAM C. HEATH.

REFERENCES crren The following references are of record in the file of this patent:

Number Number 8 11mm s'ra'ms ra'mn'rs Name Date Porter Apr. 1, 1924 Napier -1 Apr. 5, 1927 Brown May 29, 1928 Squires Jan. 5, 1932 Havill Sept. 6, 1932 Lorenzen Dec. 12, 1933 Hoover Jan. 15. 1935 Whitworth Feb. 26, 1935 Bendix Apr. 9, 1935 Weeks July 16, 1935 Warren Oct. 19, 1935 Hansen Dec. 31, 1935 Minshall July 20, 1937 Stone May 17, 1938 Nelson Feb. 11, 1941 McKee Mar. 18, 1941 Evans et a1. Sept. 30, 1941 Moss Nov. 18, 1941 Carol July 31, 1945 Hoover Sept. 23, 1947 FOREIGN PATENTS Country Date Great Britain June 18, 1931 Great Britain Mar. 24, 1932 Germany Sept. 8, 1927 Great Britain Aug. 26, 1936 Great Britain July 1, 1942 Germany Dec. 18, 1940 France June 11, 1931 

